Abstract Core C the histopathology core has been an invaluable cost effective asset to the work of the PPG since its inception. It has provided a wide variety of histological services to PPG investigators including improvements that maintain the state of the art status of the core. The histology services provided by the Core include tissue processing, paraffin embedding, sectioning, staining and immunohistochemistry. Core personnel have also assisted investigators in the collection of animal tissues for histologic studies. New services have come on-line as they have become commercially available. The Core has a laser capture microscope for tissue microdissection that was recently upgraded to support immunofluorescence detection. This has been used on Project III. The Core has also purchased a tissue microarrayer. In addition, the Core provides digital photomicrographs of selected histologic findings to program investigators. In past years, the Core's histology services have been used to a varying extent by all of the investigators - except for the old Project I in nonhuman primates which took advantage of the core in only a minor way because primate center has its own histology/pathology lab. For the upcoming PPG all three of the projects will use the core services. Dr. Thomas oversees the program and offers personal advice and assistance as needed. Ms. Gendron is an outstanding histologist who works day to day with members of the PPG team. She is highly effective. She is especially adept at getting immunohistology techniques to work. Members of the PPG are allowed to have their tissues processed at no additional charge to their individual projects. This is financially possible because of our partnership with the OHSU Knight Cancer Institute.